Reminds me of the Spider of Doom which was a similar issue where "Get/Delete" links were hidden by simple javascript to see if the user was logged in. All of a sudden pages and content on the website began to mysteriously vanish.

You know what doesn't care about Javascript and tries to click every link on your page? A search engine's web crawler.

https://thedailywtf.com/articles/The_Spider_of_Doom